Cluster Training: How to Use It to Build Muscle and Strength

I actually find it strange that more hasn’t been written about cluster training recently. There was a period of time there when it was quite popular, but now it seems that it’s fallen back into obscurity, and I have no idea why.

Cluster training is an effective tool to shock your body into new gains, as well as break up the monotony of taking a straight sets approach to your lifting. Beyond that, it’s cool, it’s different, and it’s something that will have the other members of your gym asking you, “What are you doing?”

What Is Cluster Training?

Cluster training involves using short, inter-set rest periods (usually ranging anywhere from 10–30 seconds), which act to allow us to do more reps with a heavier weight. (Note: To help paint a clearer picture of how cluster training works, throughout the article I’m going to use the running example of doing a back squat with your 5RM to explain how it works.)

Now, the difference between cluster training and traditional lifting is that in traditional lifting, using our example from above, you’d do your sets of squats for 5 reps, rest for 2-3 minutes between sets, and then move on to the second set. In cluster training what we do is break that set of 5 reps down into 4 mini-sets of 2 reps, with a 10-15 second break in between each mini-set. This effectively allows us to do 8 reps of squats with our 5RM.

I know that being able to do 3 extra reps doesn’t seem like much at first, but when you realize it equates to a 60% increase in output, you start to notice how effective cluster training can be. By employing clusters into our training in this fashion we can effectively “cheat” a set and perform more reps than we would normally be able to.

Here's a video so you can see me doing cluster training:

What Are the Benefits of Doing Clusters?

All of the benefits of cluster training arise from the ability to do more reps with a heavier weight. Whenever you’re able to keep intensity high whilst doing more reps, you’re always going to see an immediate carry over to improvements in strength and muscle gains.

The beauty of cluster training is that you can easily manipulate the sets/reps/rest scheme to make it more biased to inducing strength or hypertrophy gains, depending on what your goal is. For example, if strength is your main goal, you should aim to keep the load of the movement high (at or above 90% of your 1RM), and the reps low (mini-sets of 1-2 reps), with shorter rests (10-15s). In the case of hypertrophy, clusters allow you to take a weight that you’d normally use for building strength (i.e. a 5RM), and push the number of reps you can do with it out into the more hypertrophy-friendly reps ranges of 8-12 reps - thereby increasing the total time under tension, and placing a greater degree of mechanical stress placed upon the muscle.

Another benefit of cluster training is its ability to break through strength plateaus. Seeing as most people haven’t been exposed to cluster training methods before, it stands to reason that they will see their biggest benefit from it the first time they do it.

How Do I Do It?

There are a number of ways you can set up cluster training (and, as stated earlier, it can be altered to suit your goals), but the crux of the method lies in the short rest intervals between reps, or multiples of reps. Make sure you re-rack the bar when you rest, and utilize the entirety of the rest period - both during and after your set.

Below there are a few sets/reps schemes to get you started. Before we move onto that, it’s important to note that you can utilize cluster training on most exercises, but seeing as we’re looking for mostly strength and muscular gains, it makes sense that the best exercises to use are the bigger, compound barbell exercises.

Okay, let’s look at some ways to set up your cluster training. The first thing you’ll notice is that the set/reps for clusters are written in a weird way. Don’t freak out, they’re quite easy to understand, and I’ve given a detailed explanation on the first example so that you know exactly what you’re doing.

Strength Cluster #1:

5(4x2)-10s w/ a 5RM

In this set up you’ll do 5 total clusters (the first number), and each cluster is going to consist of 4 mini-sets of two reps (the bracketed numbers). You’re going to rest 10-seconds in between each mini-set, and you’re going to use around your 5RM in load.

Using our squat example, this is what it’d look like:

2 reps @ 5RM, rest for 10-seconds (remember to rack the bar)

2 reps, rest 10s

2 reps, rest 10 seconds

2 reps, rest 2-3 minutes

Move onto cluster #2

Repeat as above for clusters 2-5

Strength Cluster #2:

5(6x1)-15s w/ a 3-5RM

This follows the same process as the above example, except that you only do a single rep in each mini-set. The slight adjustment in reps allows you to use a heavier load, and make it a little more strength oriented.

Muscle Gain Cluster #1:

5(3x3)-15s w/ a 6RM

Again, this follows in the process as the two examples above, except that in this set up you’re going to do 3 mini-sets each consisting of 3 reps, with a 6RM. This will allow you to do 9 total reps with a 6RM, and skew the training effect more towards gaining muscle.

Muscle Gain Cluster #2:

3-4 sets of AMRAP until you hit 15 total reps – 30s w/ 85% of 1RM

In this example you’re going to find a weight that’s around 85% of your 1RM, and you’re going to do as many reps as you can (without going to complete failure) before racking the bar and resting for 30-seconds. After the short rest you’re going to again try and get as many reps as you can, before re-racking the bar and resting for another 30-seconds. Continue in this fashion until you hit a total of 15 reps.

Repeat for 3-4 total clusters. Typically you’d hit anywhere from 5-8 reps in your first mini-set, and then have the reps slowly decrease for each subsequent mini-set from there.

I like using clusters because they’re a change of pace from the regular training methods, they’re hard as hell, and they work. Bring them into your next training cycle, and I know that you’ll end up loving them as well.